Biomedical subjects
Publications and source records attributed to J Chastre.
We describe a patient who developed acute pulmonary distress with bilateral interstitial infiltrates and pleural effusion following talc pleurodesis. Talc particles, obtained by bronchoalveolar lavage, were identified by transmission electron microscopy and chemical analysis. The patient improved with corticosteroid therapy. Acute respiratory failure can be a potential hazard of talc pleurodesis.
Twenty-two adult patients who had required catheterization with a Swan-Ganz catheter and had thrombosis of the internal jugular vein were investigated for pulmonary embolism. In 4 of these, pulmonary embolism was detected by angiography, and 2 patients who died with the catheter in situ had also pulmonary embolism. In 5 out of these 6 patients prophylactic heparin treatment failed to prevent this complication. This study suggests that the Swan-Ganz catheter placement is indicated only when the value of the information to be gained exceeds the potential risk.
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The purpose of this work was to analyze, in human subjects, the shape of the aortic pressure wave from its forward and backward components calculated by use of Westerhof's model. Twenty-nine patients were studied: 11 normal subjects, 11 hypertensive patients and 7 patients with congestive heart failure. The following measurements and calculations were performed both under control conditions and during either angiotensin infusion in 5 normal subjects or nitroprusside infusion in 6 hypertensive patients: cardiac output, aortic blood pressure (catheter tip micromanometer), blood flow velocity (electromagnetic catheter-tip velocity transducer) in the ascending aorta, aortic impedance and reflection coefficients allowing the calculation of the aortic forward and backward pressure waves. The results show that the shape of aortic pressure wave in hypertensive patients is related to increased arterial wall stiffness which determines greater values and overlap of the forward and backward waves. This result is corroborated by the changes observed during angiotensin infusion in normal subjects. The shape of pressure wave in heart failure patients is dicrotic. This shape is related to smaller values and overlap of forward and backward waves. This appears related to a reduced stroke volume. During peripheral vasodilation the shape of pressure wave in hypertensive patients becomes dicrotic. However, this was mainly related to later backward waves. These results confirm that the shape of pressure waves depends both on the arterial wall stiffness and on the left ventricular performance: mainly on the stroke volume. The calculation of forward and backward waves allows a quantitative analysis of pressure waves.
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In a group of 14 patients (7 males and 7 females) ventilated artificially for acute respiratory distress syndrome, the authors defined a level of optimal expiratory positive pressure giving an FiO2 = 1, an arterial pO2 greater than or equal to 400 mmhg and/or an intrapulmonary shunt less than or equal to 15%. Improvement in arterial pO2 under such conditions would appear to be related to maximum alveolar recrutment. This optimal level of expiratory positive pressure would appear to be independent of values of total static pulmonary compliance. The long term use of this technique would seem to be encouraging.
The cardiac output (Qc), indices of left ventricular function in the isovolumic period (dp/dt/Pt), max, and during the ejection period (EF, VCF), the end diastolic and end systolic ventricular volumes, the speed of ventricular filing, the module of elasticity of the ventricular chamber (kp) and the end systolic pressure-volume relationships were measured in 20 patients (11 normal in group I and 9 with and apparently primary cardiomyopathy in group II) at rest and during progressively rapid atrial pacing. The Qc was lower and the indices of left ventricular function in the isovolumic and ejectional phases, the end systolic pressure-volume relationship and speeds of ventricular filling were decreased in group II: kp was the same in both groups of patients. At progressively higher heart rates the cardiac output slightly in both groups, the systolic volume decreased, (dp/dt/Pt) max increased, the ejection fraction and VCF were unaltered. The speeds of filling and kp were unchanged. The end systolic pressure-volume relationship increased. In group I the reduction in systolic volume seemed to be related to a greater reduction in the end diastolic volume than in the end systolic volume. In group II, the reduction of the systolic volume was related only to a reduction of the end diastolic volume.
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